The separation of air by cryogenic rectification is an energy intensive process, particularly for the generation of the refrigeration required to drive the separation. Accordingly it is desirable to keep refrigeration losses to a minimum. One potential source of refrigeration loss is the draining of liquid from one or more of the columns upon plant shut down. Moreover draining of liquid results in loss of accumulated argon which would take a substantial amount of time to replace once the plant returns to operation. Accordingly it is an object of this invention to provide a cryogenic air separation plant which can reduce liquid drain losses and the consequent refrigeration and argon loss with that liquid.